Harmonic analysis

in C minor:

C- Ab7 C- (I VIb I, tonic area expansion, to amplify this effect, alternatively C- Ab7/C C-)

in C major:

C F7 C I IVI (plagal, the C F7/C C issue works here too)

in C major:

C F D7 C, it would seem like a very normal I IV II but instead of going to the V, it returns to the I (D7 could be a tonicization of the V, but how should we consider that final C?)

Agreed for the VI and the IV, but how would you justify the minor seventh?

In the last sequence I also would have thought of a V/V, but it is curious that it resolves on the I

For me it could be a modal connection that cannot be traced back to tonal functions. If that were the case, the question itself might be flawed.... and what modes do the notes of these 3 chords have?

Hi Frank,

i mean them all in a modal context, perhaps only the last two have a bit of a bluesy color and can be considered standalone.

F F#° C, preferably with C/G at the conclusion IV V7/V I (in position 46)

or in both cases, the diminished chord replaces a secondary dominant. Do you agree?

Absolutely. The curiosity was regarding the interpretation of Ebdim D-7.

I would be inclined to think of it as a chromatic slide, but for example, I have seen that in some Dutch schools they think of it as V/V;

let me explain: Ebdim = F#dim = D7b9

D-7 = G9sus4

To me personally, it seems like a bit of a convoluted explanation...

Also because, as you rightly say, F#dim tends to resolve to a C in 4/6.

If behind your "chromatic sliding" lies the issue of tritone substitution, the matter could be viewed like this:

By replacing the dominant of D- (A7) with its tritone (Eb7), we transform the latter into Eb-7 (to have a 100% slide: E- Eb- D-) or into Eb dim (which already contains the fifth and seventh of D-7).

What do you think?